I can't upload my app

Comments

You're receiving that message because you enrolled your app in Google Play App Signing, which you shouldn't have done. From my understanding once you've enrolled your app, it cannot be undone. So the only thing you can do is change the package name of your app (App Info > Package Name), and submit it as a new app. But when submitting again, make sure you DO NOT enroll the app in Google Play App Signing. While I believe resubmitting is your only option, you may want to contact Google Play's support in case there's something else you can do.